I just completed the qt60 conversion and after i got it all together i ran it for a while and both the rings broke.Does anyone know maybe what i could of done wrong.the cylinder and piston seem to be fine and i got another set of rings so im gonna try again.Also its the 2 speed townt motor not actually the qt.ran strong as hell at first then it got to where it wouldnt idol and lost compression because the rings broke.I used gasket maker on the bottom end instead of the actual gasket if that helps....Please im anxious to get it back together because the thing was cruisin.
qt60
Re: qt60
I would guess that you put the piston in backwards. If I'm not mistaken the arrow on the top of the piston is supposed to point towards the exhaust port. If you put it in backwards I have heard that it will break the piston rings off in no time flat. My guess is that you put the piston in backwards. Check to see which way the arrow on the top is pointing and report back.
Jamie
Re: qt60
you ass. I thought I was gonna be the first on MA with the 2 speed qt60. Tommorrow I'm having the crank pressed then it'll be done. Get you bike gps'd.
Re: qt60
I'm getting ready to put my QT60 engine back together. Not going to have 2 speeds like you guys, but I will have the following:
Boyesen reeds
PW50 final drive
Mikuni VM18
K&N pod filter
PeeWee cycle oil injection blockoff
JEMCO pipe
Maybe a performance CDI unit?
What are you guys going to be using for a speedometer now that the old one is too slow? I was thinking about getting a motorcycle GPS to mount on the handlebars and removing the old gauges...
Re: qt60
yep the arrow is pointing up not down towards the exaust port.i dont think there is any damage done except for a small nick on the piston in the ring groove.i am gonna put it all back together and turn the piston around and see what goes on.thanks.im anxious to see what happens cause this thing was flying...i just have the towny 2-speed motor with pw gears and it was scootin,also what is the numbers on the main jet i have a 70,72.5 and a 65 i belive , thanks chad
Re: qt60
Nice work getting it done, Chad! I'm still working on getting my QT together- not much gets done once a baby comes along.
What pipe are you using with your bike?
We'll have to ride down to the high bridge or something once my QT is done.
Ryanc- there have been at least two other QT's with Towny engines and the 60cc cylinder swap on here, I think.
Someone should figure out a 4 petal reed setup...
Re: qt60
Be sure to report back after you turn the piston around. Let us know if it fixes your problem or not. The shop manual is so lousy that it doesn't even mention the arrow on the top of the piston. My machinist told me to be sure to point the arrow on the piston towards the exhaust port. I wouldn't have even thought it made a difference. He told me if I put the piston in backwards that it would snap the rings off on the first revolution of the crankshaft. Apparently it took a little bit longer than that for you, but it sounds like he was right.
Jamie
Re: qt60
it is common knowledge for anyone who works on motors that the arrow points to the exhaust port, it's not often it's mentioned in instructions because you should already know this if you are taking things apart.
Re: qt60
yeak i should of asked but it looks the same all around.what about the rings then ...do they need to go in any particular way...thanks chad
Re: qt60
turns out they have to weld the crank pin in, or at least one side in. So I have to wait till tomorrow to pick it up. Because the guy swore that he could get it done by yesterday and couldn't he's doing an extra $200.00, or so he says, of work for free. Has anyone else noticed there is no gasket between the case halves? Has anyone used felpro, or simular, cut-a-gasket between the halves with success? Thanks.
Re: qt60
You're supposed to use Yamabond between the case halves. It's a special sealant specifically designed for the case halves that Yamaha sells. If you clean off the mating surfaces and correctly apply the Yamabond you won't need a gasket. A lot of Volkswagen guys use it to put the case halves together on their air cooled Beetle engines too, because they have two case halves with no gasket in between them just like us.
Just a little advice because I know someone will ask: DON'T CHEAP OUT ON THE YAMABOND SEALANT! Go to your Yamaha dealer and get a tube of it. If you cut corners and try to use silicone sealant of any color, or other similar over the counter sealants you'll be sorry. Trust me. Just get the good stuff from Yamaha and get it done right the first time.
Jamie
Re: qt60
Just a thought...since you used gasket sealer instead of gasket maybe the jug is not at the right height? Don't know if that would cause your kind of problem or not.
Re: qt60
Oh and did you check the ring gap?
Re: qt60
how's the bike running chad? Did you find out what those triple tree forks were off of so I can go grab a pair too.
Re: qt60
oh check out what I did with that motor I bought from you. here
Re: qt60
here it is all done and runs strong now.... half towny-qt-yt...the suiside noped lol
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